U.S. patent number 8,155,133 [Application Number 11/405,594] was granted by the patent office on 2012-04-10 for method for handling communications over a non-permanent communication link.
This patent grant is currently assigned to Research In Motion Limited. Invention is credited to Viera Bibr, Brindusa L Fritsch, Srimantee Karmakar, Jeffrey Rogers, Michael Shenfield, Kaman B. Vitanov.
United States Patent |
8,155,133 |
Karmakar , et al. |
April 10, 2012 |
Method for handling communications over a non-permanent
communication link
Abstract
A method is disclosed for handling communications over a
non-permanent communication link. The method comprising centrally
receiving a message to transmit from a plurality of applications,
checking the availability of the non-permanent communication link,
if the non-permanent communication link is not-available, queuing
the received message for future transmission, and providing the
message to a transport/network layer if the communication link is
available.
Inventors: |
Karmakar; Srimantee
(Mississauga, CA), Rogers; Jeffrey (Scarborough,
CA), Vitanov; Kaman B. (Mississauga, CA),
Bibr; Viera (Kilbride, CA), Shenfield; Michael
(Richmond Hill, CA), Fritsch; Brindusa L (Toronto,
CA) |
Assignee: |
Research In Motion Limited
(Waterloo, CA)
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Family
ID: |
37114680 |
Appl.
No.: |
11/405,594 |
Filed: |
April 18, 2006 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20060233187 A1 |
Oct 19, 2006 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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60672082 |
Apr 18, 2005 |
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Current U.S.
Class: |
370/412;
370/469 |
Current CPC
Class: |
H04W
28/021 (20130101); H04L 47/22 (20130101); H04L
47/14 (20130101); H04L 67/2842 (20130101); H04W
4/12 (20130101); H04L 51/14 (20130101); H04L
47/10 (20130101); H04L 67/2895 (20130101); H04W
8/10 (20130101); H04L 51/38 (20130101) |
Current International
Class: |
H04L
12/28 (20060101); H04J 3/16 (20060101) |
Field of
Search: |
;370/412 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2404301 |
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Jan 2005 |
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GB |
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2404301 |
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Jan 2005 |
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GB |
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0133407 |
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May 2001 |
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WO |
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WO 01/33407 |
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May 2001 |
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WO |
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03055240 |
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Jul 2003 |
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WO |
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WO 03055240 |
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Jul 2003 |
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WO |
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Other References
European Search Report pp. 1-3. cited by other .
Canadian Intellectual Property Office, "Examiner's Requisition" for
corresponding CA Patent Application No. 2,562,182, dated Mar. 5,
2009, Canada. cited by other .
Ogilvy Renault LLP, "Response to Examiner's Requisition of Mar. 5,
2009" for corresponding CA Patent Application No. 2,562,182, dated
Sep. 2, 2009, Canada. cited by other .
State Intellectual Property Office of People's Republic of China,
"First Office Action" for corresponding CN Patent Application No.
200680000245.8, dated Feb. 12, 2010, China. cited by other .
European Patent Office, "European Search Report" for corresponding
EP Patent Application No. 06741393.0 dated Sep. 20, 2007, Germany.
cited by other .
European Patent Office, "Communication Pursuant to Article 94(3)
EPC" for corresponding EP Patent Application No. 06741393.0 dated
Mar. 19, 2008, Germany. cited by other .
Ipulse, Response to EPO Communication of Mar. 19, 2008, for
corresponding EP Patent Application No. 06741393.0, dated Jul. 30,
2008, United Kingdom. cited by other .
Canadian Intellectual Property Office, "International Search
Report" for corresponding PCT Application No. PCT/CA2006/000615,
dated Aug. 25, 2006, Canada. cited by other .
State Intellectual Property Office of People's Republic of China,
"Second Office Action for corresponding Chinese Patent Application
No. 200680000245.8", dated Jul. 13, 2011, China. cited by
other.
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Primary Examiner: Blanton; John
Attorney, Agent or Firm: Norton Rose Canada LLP
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is based on, and claims benefit of 35 U.S.C.
.sctn.119(e) of Provisional Patent Application No. 60/672,082 filed
Apr. 18, 2005, which is hereby incorporated by reference.
Claims
We claim:
1. A method in a wireless electronic device for handling
communications over a non-permanent communication link in a
network, the wireless electronic device comprising a processor for
executing code to implement a communication management unit for
carrying out a communication management function, the communication
management unit including a dispatching unit for carrying out a
message dispatching function and a queuing control unit for
carrying out a message queuing control function, said method
comprising: centrally receiving, at the dispatching unit in the
communication management unit, messages for transmission from a
plurality of applications resident on the wireless electronic
device; centrally checking, at the queuing control unit in the
communication management unit, using a status signal received from
a transport/network layer, whether said non-permanent communication
link is available for transmission of messages, the status signal
being indicative of availability of the non-permanent communication
link; when said non-permanent communication link is not-available,
queuing said received messages in one of at least one queue in the
communication management unit for future transmission; and
providing said messages from the queue to the transport/network
layer when said communication link is available; wherein the
non-permanent communication link has an air interface with
non-permanent coverage; and wherein the non-permanent communication
link is available when the wireless device is able to establish
communication with a server in the network, and the non-permanent
communication link is not-available when the wireless device is
unable to establish communication with the server in the
network.
2. The method as claimed in claim 1, wherein said queuing of said
received messages for future transmission comprises selecting, at
the dispatching unit, an appropriate queue amongst a plurality of
queues in the communication management unit for each received
message and said received message is provided to said
transport/network layer from said selected appropriate queue.
3. The method as claimed in claim 2, wherein said plurality of
queues comprises one of a queue per application and a queue per
destination server.
4. The method as claimed in claim 1, wherein said status signal is
received at the queuing control unit in response to at least one
event provided by said transport/network layer.
5. The method as claimed in claim 1, wherein said status signal is
received at the queuing control unit in response to a request from
the communication management unit for a status check.
6. The method as claimed in claim 1, wherein said queuing is
performed in a given queue having a given limit.
7. The method as claimed in claim 6, wherein said given limit is
created using at least one of a maximum number of messages to send
for a given application, the given application being one of the
plurality of applications where the plurality of queues comprises a
queue per application.
8. The method as claimed in claim 6, wherein when said given queue
reaches said given limit, a notification is provided to said given
application.
9. The method as claimed in claim 8, wherein said application
notifies a user upon receipt of said notification.
10. A non-transitory computer readable memory comprising
instructions which when executed by a processor causes the
processor to perform the steps of: implementing a communication
management unit for carrying out a communication management
function, the communication management unit including a dispatching
unit for carrying out a message dispatching function and a queuing
control unit for carrying out a message queuing control function;
centrally receiving, at the dispatching unit in the communication
management unit, messages for transmission from a plurality of
applications resident on the wireless electronic device, the
wireless electronic device being adapted for handling
communications over a non-permanent communication link in a
network; centrally checking, at the queuing control unit in the
communication management unit, using a status signal received from
a transport/network layer, whether said non-permanent communication
link is available for transmission of messages, the status signal
being indicative of availability of the non-permanent communication
link; when said non-permanent communication link is not-available,
queuing said received messages in one of at least one queue in the
communication management unit for future transmission; and
providing said messages from the queue to the transport/network
layer when said communication link is available; wherein the
non-permanent communication link has an air interface with
non-permanent coverage; and wherein the non-permanent communication
link is available when the wireless device is able to establish
communication with a server in the network, and the non-permanent
communication link is not-available when the wireless device is
unable to establish communication with the server in the
network.
11. The computer readable memory as claimed in claim 10, wherein
said queuing of said received messages for future transmission
comprises selecting, at the dispatching unit, an appropriate queue
amongst a plurality of queues in the communication management unit
for each received message and said received message is provided to
said transport/network layer from said selected appropriate
queue.
12. The computer readable memory as claimed in claim 11, wherein
said plurality of queues comprises one of a queue per application
and a queue per destination server.
13. The computer readable memory as claimed in claim 10, wherein
said status signal is received at the queuing control unit in
response to at least one event provided by said transport/network
layer.
14. The computer readable memory as claimed in claim 10, wherein
said status signal is received at the queuing control unit in
response to a request from the communication management unit for a
status check.
15. The computer readable memory as claimed in claim 10, wherein
said queuing is performed in a given queue having a given
limit.
16. The computer readable memory as claimed in claim 15, wherein
said given limit is created using at least one of a maximum number
of messages to send for a given application, the given application
being one of the plurality of applications where the plurality of
queues comprises a queue per application.
17. The computer readable memory as claimed in claim 15, wherein
when said given queue reaches said given limit, a notification is
provided to said given application.
18. The computer readable memory as claimed in claim 17, wherein
said application notifies a user upon receipt of said
notification.
19. A wireless electronic device for handling messages from a
plurality of applications resident on the device to be transmitted
from a transport/network layer on the device over a non-permanent
communication link in a network, the device having a processor
coupled to a memory having computer-executable instructions encoded
thereon, the instructions, when executed, causing the processor to
implement: a central communication management unit for carrying out
a communication management function, the central communication
management unit comprising: a dispatching unit for receiving
messages to transmit from said plurality of applications; a queuing
control unit for checking, using a status signal received from a
transport/network layer, whether said non-permanent communication
link is available for transmission of messages, the status signal
being indicative of availability of the non-permanent communication
link; and at least one queue for storing received messages when
said non-permanent communication link is not-available, and for
providing said messages to the transport/network layer when said
communication link is available; wherein the non-permanent
communication link has an air interface with non-permanent
coverage; and wherein the non-permanent communication link is
available when the wireless device is able to establish
communication with a server in the network, and the non-permanent
communication link is not-available when the wireless device is
unable to establish communication with the server in the
network.
20. The device as claimed in claim 19, wherein said queue comprises
a plurality of queues, wherein said queuing control unit is further
for selecting an appropriate queue amongst said plurality of queues
for said received messages and each received message is provided to
said transport/network layer from said selected appropriate
queue.
21. The device as claimed in claim 20, wherein said plurality of
queues comprises one of a queue per application and a queue per
destination server.
22. The device as claimed in claim 19, wherein said queuing control
unit is further for producing an enable signal when said
non-permanent communication link is available; and further wherein
said queue is further for storing said received message in absence
of said enable signal and for forwarding said received message in
presence of said enable signal.
23. The device unit as claimed in claim 19, wherein said queuing
control unit receives said status signal in response to at least
one event provided by said transport/network layer.
24. The device as claimed in claim 19, wherein said queuing control
unit receives said status signal in response to a request from the
communication management unit for a status check.
25. The device as claimed in claim 19, wherein said queue comprises
a plurality of queues, wherein said queuing control unit is further
for selecting an appropriate queue amongst said plurality of queues
for said received message and for providing said received message
from said selected appropriate queue, and further wherein a given
queue of said plurality of queues has a given limit.
26. The device as claimed in claim 25, wherein said given limit is
created using at least one of a maximum number of messages to send
for a given application.
27. The device as claimed in claim 25, wherein said given queue
reaches said given limit, further wherein when said given queue
reaches said given limit, a notification is provided to a given
application.
28. The device as claimed in claim 27, wherein said application
notifies a user upon receipt of said notification.
Description
FIELD OF APPLICATION
The instant application relates to the field of communications.
More precisely, this application pertains to a method for handling
communications over a non-permanent communication link.
BACKGROUND OF THE ART
Wireless data communication devices are now widespread due to the
fact that they are popular with users.
Such wireless data communication devices are usually provided with
a plurality of applications such as an electronic messaging
application, an Internet browser application, an instant messaging
(IM) application, etc.
In use, a wireless data communication device may be located
temporarily in a zone where the wireless connection is not
available anymore. The wireless data communication device is hence
out of coverage.
In such case, outbound messages (also referred to as outgoing
messages or messages to transmit) generated from the applications
running on the wireless communication device will therefore become
undeliverable to any server. More precisely, for each outbound
message, the transport/network layer reports individually to each
application that its message transmission failed. The application
must then be programmed accordingly to handle such failure.
The skilled addressee will appreciate that such situation creates a
large overhead especially in the case where there is a large number
of messages to transmit by a plurality of applications.
The skilled addressee will further appreciate that frequent radio
communication attempts will significantly reduces the battery life
of a wireless data communication device.
There is a need for a method that will overcome at least one of the
above-identified drawbacks.
Features of the application will be apparent from review of the
disclosure, drawings and description below.
DESCRIPTION OF THE DRAWINGS
In order that the application may be readily understood,
embodiments are illustrated by way of example in the accompanying
drawings.
FIG. 1 is a block diagram which shows a system where the method for
handling communications over a non-permanent communication link may
be advantageously used;
FIG. 2 is a block diagram showing a plurality of communication
applications communicating with a transport/network layer using a
communication management unit in accordance with an embodiment;
FIG. 3 is a block diagram showing, inter alia, an embodiment of the
communication management unit; in this embodiment, the
communication management unit comprises a dispatching unit, a
plurality of queues and a queue control unit;
FIG. 4 is a flowchart which shows a method where a communication
application communicates according to an embodiment; a check to
find out if a communication link is available is performed;
FIG. 5 is a flowchart which shows a method where a message is
provided to the transport/network layer for transmission in the
case where a communication link is available;
FIG. 6 is a flowchart which shows a method where a message is
provided to a queue in an embodiment; according to a first step, a
suitable queue is selected and according to a second step, the
message is provided to a selected suitable queue; and
FIG. 7 is a flowchart which shows a method which takes into account
what happens when a check is performed to find out if a
communication link is available.
DETAILED DESCRIPTION
According to a first aspect, there is provided a method for
handling communications over a non-permanent communication link.
The method comprises centrally receiving a message to transmit from
at least one application among a plurality of applications,
checking the availability of the non-permanent communication link,
if the non-permanent communication link is not-available, queuing
the received message for future transmission, and providing the
message to a transport/network layer if the communication link is
available.
According to another aspect, there is provided a communication
management unit for handling communications from a plurality of
applications to a transport/network layer and over a non-permanent
communication link. The communication management unit comprising: a
dispatching unit receiving a message to transmit at least one
application among the plurality of applications; a queuing control
unit for checking the availability of the non-permanent
communication link; and a queue for queuing the received message if
the non-permanent communication link is not-available, and for
providing the message to a transport/network layer if the
communication link is available.
In the following description of the embodiments, reference to the
accompanying drawings is by way of illustration of examples. It
will be understood that other embodiments may be made without
departing from the scope of the application disclosed.
Now referring to FIG. 1, there is shown an embodiment of a system
wherein the method for handling communications over a non-permanent
communication link disclosed below may be advantageously used.
The system comprises a server unit 10, a network 12, a plurality of
transmitting devices 16 and a plurality of user devices 18.
The server unit 10 is adapted for providing a signal to send to the
plurality of user devices 18 over a communication link. In the
present embodiment, the communication link is an air interface and
is not shown. The server unit 10 may comprise any type of
processing unit that is connected permanently or temporarily with
the plurality of user devices 18.
The network 12 comprises at least one of a Local Area Network
(LAN), a Metropolitan Area Network (MAN) and a Wide Area Network
(WAN). In an embodiment, the network 12 comprises a Wide Area
Network which is the Internet.
The plurality of transmitting devices 16 comprises wireless
transmitters adapted to transmit data to the plurality of user
devices 18.
The plurality of user devices 18 comprises devices that are adapted
to process at least data. In one embodiment, shown in FIG. 1, the
plurality of user devices 18 are wireless user devices. It should
be appreciated that various types of devices may be used such as
Personal Digital Assistants (PDAs), smart phones, etc. In an
embodiment, the plurality of user devices 18 comprises
BlackBerry.TM. devices which are manufactured by Research In Motion
Limited.
More precisely, the server unit 10 is adapted to provide to the
network 12, inter alia, a signal to send.
At least one of the plurality of transmitting devices 16 is adapted
to transmit a signal to at least one of the plurality of user
devices 18.
Now referring to FIG. 2, there is shown how a plurality of
applications 20 communicates with a transport/network layer 24. It
should be appreciated that in the embodiment disclosed herein, the
plurality of applications 20 is located on at least one of the
plurality of user devices 18 (from FIG. 1). Alternatively, the
plurality of applications may be located on the server unit 10
(from FIG. 1).
A communication management unit 22 is provided and is adapted for
receiving at least one message to transmit which is provided by the
plurality of applications 20. The communication management unit 22
is further adapted for providing the provided messages to transmit
to the transport/network layer 24.
In an embodiment herein, the communication management unit 22 is
implemented as a system-level container. It will be further
appreciated that the communication management unit 22 is adapted
for listening for events related to the network coverage status of
the user device 18. These events are generated by a lower-level
transport layer, also referred to as transport/network layer 24.
The transport/network layer 24 may use a polling solution where it
periodically attempts to open a successful connection to the
network to detect the status of the wireless device 18. However,
the transport layer designer may use some other solutions to
consistently update the status of the wireless device 18. When the
communication management unit 22 receives an event from the
transport layer indicating that the device is out of coverage, it
starts queuing messages provided by anyone of the plurality of
applications 20 and does not attempt to transmit any through the
transport/network layer 24. It will be appreciated and further
shown below that a queue may be chosen according to various
criteria. In fact there may be a queue per destination server (i.e.
the criterion is the destination server of a message), as in an
embodiment, a queue per application (i.e. the criteria is a number
of application), a single queue, or the like, depending on
requirements. When the communication management unit 22 receives an
event from the transport layer indicating that the device is in
coverage, it resumes transmission of messages through the
transport/network layer 24. It will be appreciated that in one
embodiment, the communication management unit 22 is also aware of
the different servers that the plurality of applications might
communicate with. Such information may be obtained at the
application installation time, or, as in an embodiment, when a
handshake between the system containing the communication unit and
each server initially takes place. After such handshake, the
application communicating with that server may be installed. It
will be appreciated that each server has to be notified that the
wireless device 18 is back in coverage and any messages queued on
the server should then be sent to the applications, which can be
done by sending any type of messages to the server. So if there is
at least one application message to send to the server, the
application message is sent. Alternatively, a special "Heartbeat"
message may be sent. When the server successfully receives a
message from the wireless device 18 that was previously
unreachable, the server resumes transmission of messages to this
device.
In the embodiment disclosed, the plurality of applications 20
comprises a first communication application 26, a second
communication application 28 and a third communication application
30.
Still in the embodiment disclosed in FIG. 2, the first
communication application 26 provides a first message to transmit
to the communication management unit 22, while the second
communication application 28 provides a second message to transmit
to the communication management unit 22, and the third
communication application 30 provides a third message to transmit
to the communication management unit 22.
The communication management unit 22 receives a status signal
provided by the transport/network layer 24. The status signal is
indicative of the availability of the communication link which is
intended to be used for transmitting the messages. The
communication management unit 22 provides at least one message to
send to the transport/network layer 24 of the user device 18.
The transport/network layer 24 transmits the message to send over
the communication link (not shown here).
Now referring to FIG. 3, there is shown an example of the
communication management unit 22.
In the embodiment disclosed in FIG. 3, the communication management
unit 22 comprises a dispatching unit 36, a plurality of queues 32,
and a queuing control unit 44.
The dispatching unit 36 receives the plurality of messages to
transmit provided by the plurality of applications 20.
The dispatching unit 36 is adapted for sorting the plurality of
messages according to at least one criterion. In one embodiment,
the criterion is the destination server for the message. In fact,
the skilled addressee will appreciate that a first given message
may be intended to be delivered to a first server while a second
given message may be intended to be delivered to a second given
server.
Each of the plurality of queues 32 is used for storing at least one
of the plurality of messages to transmit provided by the plurality
of applications 20 to the communication management unit 22.
In one embodiment, the number of queues of the plurality of queues
32 depends on the at least one criterion disclosed above.
The communication management unit 22 further comprises a queuing
control unit 44. The queuing control unit 44 is adapted for
controlling the plurality of queues 32. In the embodiment
disclosed, the queuing control unit 44 receives a status signal
provided by the transport/network layer 24 and provides a plurality
of corresponding enable signals to each queue of the plurality of
queues 32. The enable signal provided to a given queue is
indicative of an available communication link and is therefore used
to empty the given queue. It will be appreciated that the enable
signal may be provided to each of the plurality of queues 32
according to various strategies depending on the type of
queues.
Each of the queues of the plurality of queues 32 provides
corresponding queued messages to send to the transport/network
layer 24.
In the embodiment disclosed in FIG. 3, the plurality of queues 32
comprises a first queue 38, a second queue 40 and a third queue 42.
It will be appreciated by the skilled addressee that in an
embodiment no maximum size is set for a given queue. However, a
limit is preferably set using a number of pending messages to send
from any one of the plurality of applications 20. Still in an
embodiment, the limit is the lower of a maximum number of outbound
pending messages for a given application stated by either the
system within which the given application is running or the given
application itself at the installation time. The limit is imposed
by the communication management unit 22. Once the limit is reached,
the given application is notified. It is up to the given
application to prevent the user from sending any further messages.
The communication management unit 22 rejects then all message from
the given application after the limit is reached. The application
has then to perform the necessary handling of the rejected
messages.
The queuing control unit 44 disclosed in FIG. 3 may provide a first
enable signal to the first queue 38, a second enable signal to the
second queue 40 and a third enable signal to the third queue 42
when the communication link is available.
In response to the first enable signal, the first queue 38 may
provide corresponding queued messages to send to the
transport/network layer 24, while in response to the second enable
signal, the second queue 40 may provide corresponding queued
messages to send to the transport/network layer 24 and in response
to the third enable signal, the third queue 42 may provide
corresponding queued messages to send to the transport/network
layer 24.
Now referring to FIG. 4, there is shown an embodiment which shows
how a communication application communicates according to an
embodiment.
According to step 50, a request for transmitting a message is
received from a communication application. The request is received
by the communication management unit 22.
In one embodiment, the message is directly provided to the
communication management unit 22.
According to step 52, a check is performed in order to find out if
the communication link is available. In an embodiment, the check is
performed by checking the status of a state variable belonging to
the queue for the outgoing message. The state variable is set to
one of "Enabled" (i.e. the communication link is available) or
"Disabled" (i.e. the communication link is not available). The
skilled addressee should appreciate that the state variable is set
to one of "Enabled" and "Disabled" depending on the received event
provided by the transport/network layer 24. It should be
appreciated that preferably the state variable is maintained
independently for each queue as there may be additional reasons to
not send any messages to a server even when the device is in
coverage, such as the remote server being down for instance. The
state of the queue is checked to see if new messages should be sent
or kept queued.
In the case where the communication link is not available and
according to step 58, the message to transmit is provided to a
queue. In an embodiment, the message is provided to a queue of the
plurality of queues 32.
In the case where the communication link is available and according
to step 54, the message is provided to the transport/network layer
24 (see FIG. 2) for transmission.
According to step 56, the message is transmitted by the
transport/network layer 24.
Referring to FIG. 5, there is shown how the message to transmit is
provided to the transport/network layer 24 (see FIG. 2) for
transmission according to one embodiment.
According to step 60, the message to transmit is provided to a
corresponding queue. As explained above, the message to transmit is
provided to a corresponding queue depending on various criteria. In
this embodiment, the message to transmit is provided to a
corresponding queue using the dispatching unit 36 (see FIG. 3).
According to step 62, the corresponding queue is emptied to provide
the queued message to the transport/network layer 24. Still in this
embodiment, the corresponding queue is emptied using an enable
signal provided by the queuing control unit 44 (see FIG. 3).
Now referring to FIG. 6, there is shown how the message to transmit
is provided to a queue in the case where the communication link is
not available.
According to step 70, a suitable queue is selected for the message
to transmit. The suitable queue is selected amongst the plurality
of queues 32 using the dispatching unit 36 (see FIG. 3) depending
on at least one criterion as explained above.
According to step 72, the message to transmit is provided to the
selected suitable queue.
Now referring to FIG. 7, there is shown what happens in the case
where a communication link becomes available.
According to step 80, a status check is performed at the
transport/network layer 24 (see FIG. 2).
According to step 82, a check is performed in order to find out if
the communication link is now available.
In the case where the communication link is available and according
to step 84, an enable signal is provided to the plurality of queues
32.
According to step 86, an indication is provided to a remote unit.
In fact, the indication is used to inform the remote unit to which
user device 18 it is connected with via the communication link so
that user device 18 may be reregistered on the remote unit.
According to step 88, the plurality of queues 32 are emptied.
The skilled addressee will appreciate that without the
communication management unit 22, each of the plurality of
applications 20 would have to individually listens for and handle
the coverage events. Moreover, the skilled addressee will further
appreciate that other various types of events have to be handled.
For instance, "Radio On/Off" events are produced when a user turns
the radio/wireless coverage off or on. The skilled addressee will
appreciate that the communication management unit 22 is capable of
handling all events related to network coverage and translating
them into whether or not it is possible to send a message.
It should be noted that the present invention can be carried out as
a method, can be embodied in a system, a computer readable medium
(or memory) or an electrical or electro-magnetical signal.
Although the above description relates to a specific embodiment as
presently contemplated by the inventor, it will be understood that
the application in its broad aspect includes mechanical and
functional equivalents of the elements described herein.
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